CODODGE2500MAN

So my truck is acting up!!!

Fires up perfect in the morning. Turn key to on and FP gauge goes from 15 (what it read when shut down) to 0, (hear the FASS run) and then FP back to 15. Fires right up.

Run to work (15 miles) shut down. If I turn key back to "on," FP goes from 15 to 0 and stays there. Can't hear the fass run. Bump starter, Fass runs for 2 seconds then shuts off. FP goes from 0 to 15 and then back to 0. Truck turns over for about 3-5 seconds, then finally struggles to start.

If I get to work and wait till truck is cool (few hours) fires up just fine (like it does in the morning).

No CEL, runs great once its fired up.

Is it a relay? Which one? Or is this the VP44 again?

FP has been at 15 idle, 13 min at WOT...

Thanks for the help....

Mike Holmen

I've found that VP trucks are hard starting when warm when fuel pressure is above 5 psi. Really bad when its hot outside. I run a walbro 395, efi adjustable fuel reg, stock 02 canister, 1/2in hose, stock fuel filter, stock fuel line from fuel canster to VP. Currently I run 28 psi at the VP, and have run 60psi at times. I have over 400000kms on the current VP, stock not a rebuild.

Hows your fass rig up? You still running stock fuel filter? What fuel lines and fuel module/canister stuff have you done. Some stuff works well, some doesn't work well. I've owned my truck since new and its been adjusted since day one, and a few times too many times. Done tons of fass installs over the years.

KATOOM

First off, I feel that your fuel pressure is to low. I'm an advocate that if fuel pressure isn't at or above 15 all the time then the VP is running hotter than it should. There's no point in having a higher volume / higher pressure fuel pump if someone's just going to run the same pressures as the OEM lift pump. The VP must have more fuel than the overflow valve setting of 14-16 psi otherwise the fuel isn't doing the job that the VP needs, which is to cool it.

As for the hard hot start. You could be experiencing the the FASS over-pressurizing the VP during engine cranking. This is only a problem when the engine is hot. An easy way to determine if this is your issue is, when you are experiencing the hard hot start, simply pull the single inline fuse for the FASS. NOT any of the OEM fuses. Then with that FASS fuse pulled, try starting the engine. If it starts like normal then there's your problem. Just remember to put the fuse back immediately so the VP doesn't continue to run with no fuel pressure. If that works then you can install a simple relay to delay fuel pumping during engine cranking. Very easy.

If it doesn't start normally with that FASS fuse temporarily pulled then say so because there's another problem.

Mike Holmen

I just use my fuel pressure gauge for a judge. I try not to crank it until pressure drops below 5 psi, if I forget, just keep on cranking and pretend that its a common rail.